On one level, the story of the Coultson paper is simple: Decades ago, a seemingly small omission happened to slip past regulators. And yet the consequences of that one statistical sleight of hand, and the government's failure to notice it, are immense. Between 1992 and 2017, chlorpyrifos was one of the most heavily used pesticides in the U.S., with some 450 million pounds of it sprayed on crops. what is this mean